Consciousness: Sleep, Dreams, and Psychoactive Drugs

Consciousness

Definition and States

Consciousness refers to our subjective experience of the world, our bodies, and our mental perspectives. It encompasses both waking consciousness and altered states.

• Waking consciousness: Awareness of self and environment.

• Altered states: Includes sleep paralysis, locked-in syndrome, out-of-body experiences, near-death experiences, mystical experiences, hypnosis, meditation, and effects of psychoactive drugs.

Sleep

Circadian Rhythm

Circadian rhythms are biological cycles that occur over approximately 24 hours, regulating sleep, hunger, and other bodily functions.

• Regulation: Controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus, which synchronizes with light information from the retina.

• Functions: Influences sleep-wake cycle, body temperature, hormone production, and blood pressure.

What is Sleep?

Sleep is a state of low physical activity and reduced awareness, associated with the secretion of several hormones:

• Melatonin

• Follicle stimulating hormone

• Luteinizing hormone

• Growth hormone

Stages of Sleep

Sleep occurs in 5 stages, cycling every 90 minutes:

• Stages 1-4: NREM (Non-Rapid Eye Movement) sleep; no eye movements, fewer dreams.

• Stage 5: REM (Rapid Eye Movement) sleep; vivid dreams, quick eye movements.

Stage 1: Transition

• Transition from wakefulness to sleep (10-15 minutes).

• Brain waves slow down.

• Dreams resemble photos.

Stage 2: Falling Asleep

• Further slowing of brain waves.

• Appearance of sleep spindles and K-complexes (may help maintain sleep and memory storage).

• Comprises about 65% of total sleep; lasts around 20 minutes.

Stages 3 and 4: Deep Sleep

• Characterized by delta waves.

• Crucial for feeling rested; growth hormone production increases.

• Children spend more time in these stages than elderly.

• Suppressed by alcohol.

• Stage 4 is the hardest to awaken from.

Stage 5: REM Sleep

• Rapid eye movements; brain waves similar to wakefulness.

• Antonia (muscle paralysis); only eye and inner ear movements.

• REM rebound: increased REM after deprivation.

• Considered essential for health.

Hypnagogic State

The hypnagogic state is the transitional phase between wakefulness and sleep, often accompanied by vivid imagery:

• Visual, somatic, and auditory hypnagogic imagery

• Myoclonic/hypnic jerk: Sudden muscle contractions as one falls asleep.

Why Do We Sleep?

• Adaptive (Preserve & Protect Hypothesis): Sleep restores resources and protects from predatory risks, though it makes us vulnerable.

• Restorative (Restore & Repair Hypothesis): Sleep replenishes the body, consolidates memory, supports learning and cognitive function, especially during slow-wave sleep.

• Essential: Necessary for growth and brain development, but the full reasons remain unclear.

Sleep Deprivation & Displacement

• Sleep deprivation: Degeneration of neurons in the brainstem, ADHD-like symptoms, increased risk of illness and substance abuse. Effects comparable to a blood alcohol concentration (BAC) of 0.07.

• Sleep displacement: Prevented from sleeping at the normal time (e.g., jet lag, caffeine before bed).

Disruptions of Normal Sleep

• Jet lag: Mismatch between internal circadian cycles and environment, causing fatigue and irritability.

• Rotating shift work: Changes in work schedule disrupt circadian rhythm, leading to exhaustion, sleep problems, depression, and anxiety. Bright light therapy can help realign biological clocks.

Effects of Shift Work

• Shift work can age the brain by more than 6 years.

• Associated with decline in memory, processing speed, and overall brain power.

• Effects are reversible (~5 years to recover).

Daylight Savings Time & Car Accidents

Changes in sleep patterns due to daylight savings time are linked to increased car accidents, especially after the spring shift.

Sleep Deprivation & Mental Health

• Increased stress and emotional reactivity.

• Lack of emotional regulation due to biological changes (e.g., amygdala activation without frontal cortex regulation).

Extreme Case: Peter Tripp

• Stayed awake for 200 hours; experienced hallucinations, paranoia, delusions, and personality changes.

• Died at 73 of a stroke.

Sleep Hygiene for Students

• Maintain regular sleep-wake schedule.

• Quiet sleep environment.

• Avoid caffeine after lunch and stimulating activities before bed.

• Use bed only for sleep.

Sleep Disorders

Insomnia

• Difficulty falling or staying asleep for at least 3 nights a week, for at least 1 month.

• 9-20% of people experience insomnia; higher rates among students (~25%).

• Associated with ADHD, depression, and employment issues.

• Treatment: Psychotherapy and/or hypnotics (e.g., Lunesta, Ambien); concerns about tolerance and side effects.

Paradoxical Insomnia

• Sleep-state misperception: Belief of sleep deprivation despite normal sleep cycle.

• Distress, anxiety, fatigue; cause unclear but linked to brain arousal during sleep.

Night Terrors & Sleep Apnea

• Night terrors: Sudden waking episodes with screaming, sweating, confusion; most common in children (3-8), usually harmless.

• Sleep apnea: Blockage of airway during sleep; associated with SIDS.

Narcolepsy

• Rapid and unexpected onset of sleep, directly into REM.

• Cataplexy (sudden loss of muscle tone).

• Associated with lack of orexin.

Other Sleep Disorders

• REM behaviour disorder: Not paralyzed during REM, can act out dreams.

• Somnambulism: Walking while fully asleep, vague consciousness; occurs in stage 3 sleep, safe to wake.

Dreams

Freud's Theory

• Dreams as unconscious wish fulfillment.

• Latent content: Hidden psychological meaning.

• Manifest content: Actual storyline of the dream.

• Symbolic interpretation (e.g., objects in dreams may represent unconscious desires).

Evolutionary Theory

• Problem-solving theory: Dreams help process stressful events and daily concerns.

• Critical information for survival is reconsidered and reprocessed during dreams.

• Cross-cultural differences in dream content (e.g., Kurdish vs. Finnish children).

Neuroscience Theory

• Activation-synthesis theory: Dreams are the brain's attempt to make sense of random neural activity during sleep.

• Dream scenarios reflect dreamer's fears, emotions, and concerns.

• Motivational and emotional centers (limbic system) active during REM; less activation of prefrontal cortex.

Psychoactive Drugs

Definition

Psychoactive drugs are substances that contain chemicals similar to those found naturally in the brain, altering neurotransmission and affecting emotions, perceptions, and behaviors. They can create physiological or psychological dependence.

Stimulants

• Speed up activities of the nervous system, enhancing wakefulness and alertness.

• Caffeine: Most commonly used; blocks adenosine, increasing arousal.

• Cocaine: Small doses produce euphoria, energy, and confidence; large doses cause irritability and aggression. Blocks dopamine reabsorption.

• Amphetamines: Strong stimulants (e.g., Dexedrine, Benzedrine, methamphetamine); stimulate dopamine release, can cause neurological and physical problems.

• ADHD medications: (e.g., Adderall, Vyvanse) increase dopamine, serotonin, norepinephrine; improve wakefulness and coping with stress.

• MDMA: Also a hallucinogen; increases serotonin, heightens sensations, increases social bonding, can alter brain structure with chronic use.

Hallucinogens (Psychedelics)

• Produce hallucinations or changes in perception (e.g., LSD, psilocybin, ayahuasca, marijuana, ecstasy, salvia).

• Interest in therapeutic value for mystical experiences and treatment-resistant challenges.

• MDMA & LSD: Alter serotonin, perception, and neural communication; LSD produces vivid hallucinations and time distortions.

Marijuana (THC)

• Effects are excitatory, depressive, and mildly hallucinatory.

• Triggers spontaneous ideas, distorted perceptions, increased sensitivity to stimuli.

• Memory impairment due to cannabinoid receptors in hippocampus.

• Prolonged use can impair cognitive function and reduce dopaminergic function (reversible).

• High THC content linked to cannabis-induced psychosis (hallucinations, paranoia, disorganized thinking).

• Today's cannabis is much stronger than in the 1970s (10x more THC).

Depressants

• Reduce arousal and stimulation by decreasing neurotransmission and electrical activity.

• Includes alcohol, opioids, benzodiazepines, barbiturates.

• Used to treat anxiety, panic, and sleep disorders.

Alcohol

• Most commonly used depressant; stimulating at low doses, depressant at higher doses.

• Lowers inhibition, impairs judgment, magnifies emotions.

• Females experience effects more heavily (same weight, higher BAC).

• Balanced-placebo design: Expectations influence social behavior more than physiological effects.

Your Brain on Alcohol

BAC Range	Effects
0.01 - 0.05	Behavior and judgment slightly affected; not intoxicated
0.03 - 0.12	Blurred vision, slurred speech, impaired coordination, euphoria
0.09 - 0.25	Alcohol poisoning, senses severely impaired
0.25 - 0.35	Coma risk, compromised respiration and circulation
0.45	Alcohol poisoning may cause death

Depressants: Sedatives

• Barbiturates: Induce sleep or relaxation; psychologically and physically addictive; deadly with alcohol.

• Benzodiazepines: Treat anxiety and panic; highly addictive; excessive use leads to tolerance and memory impairment; deadly with alcohol.

Quaaludes

• Methaqualone: CNS depressant, sedative, and hypnotic (increases GABA).

• Popular in 1970s; banned due to widespread recreational use.

Opioids

• Derived from poppy seeds; act on brain's opioid receptors to produce euphoria.

• Includes prescription drugs (oxycodone, morphine, fentanyl) and illegal drugs (heroin).

• Slows brain activity and respiration; highly addictive due to dopamine surge.

• Cycle of addiction: drug used to avoid withdrawal rather than to feel good.

Summary Table: Sleep Stages

Stage	Key Features
Stage 1	Transition, slow brain waves, light sleep, hypnagogic imagery
Stage 2	Sleep spindles, K-complexes, memory consolidation, 65% of sleep
Stage 3	Delta waves, deep sleep, growth hormone production
Stage 4	Deepest sleep, hardest to awaken
Stage 5 (REM)	Rapid eye movements, vivid dreams, muscle paralysis

Key Equations

• Blood Alcohol Concentration (BAC) comparison: Sleep deprivation effects similar to BAC of 0.07

$\text{BAC} = 0.07$

Additional info: Some explanations and definitions have been expanded for clarity and completeness, including the mechanisms of sleep stages, drug effects, and the role of the SCN in circadian rhythms.